Here in Dawnson County, much of the early history is concerned with the pioneer trails to the west. The Mormon Trail to Utah and the first transcontinental railroad passed through here on the north side of the Platte River; the Oregon Trail and the Pony Express followed the south side of the Platte. Indian trouble was not uncommon here in the early days of settlement. The Plum Creek Massacre occurred in 1864 when Sioux Indians attacked a wagon train, killing several men and taking prisoners at a site near here in Phelps County. Also near here, in 1867 a group of Cheyenne led by Chief Turkey Leg cut the telegraph line, derailed a locomotive, and killed several Union Pacific Railroad employees. The town of Cozad, near here, lies directly on the 100th Meridian, considered an important goal in the building of the first transcontinental railroad. When the tracks reached this point in 1866, some 250 businessman, senators, congressmen and other notables came here to celebrate. The 100th Meridian is often cited as the "line of aridity," west of which rainfall is usually insufficient to support non-irrigated agriculture.